JP2012227647A - Spatial sound reproduction system by multi-channel sound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce three-dimensional multi-channel sound under an indoor acoustic environment.SOLUTION: A spatial sound reproduction system 10 comprises: a plurality of spatially arranged speakers 30-1 to 30-N which are spatially arranged in a distributed manner under an indoor acoustic environment for reproducing three-dimensional multi-channel acoustic signals; speakers arranged close to ears 40 which are composed of a plurality of speakers arranged in preset positions close to ears of listeners in respective listening positions for reproducing binaural reproduction acoustic signals converted from the three-dimensional multi-channel acoustic signals; and a spatial sound reproduction device 20 which adjusts a time difference of the binaural reproduction acoustic signals from the three-dimensional multi-channel acoustic signals so as to make reproduction sound reproduced by the plurality of spatially arranged speakers is in phase with reproduction sound reproduced by speakers arranged close to ears, and also generates binaural reproduction acoustic signals by attaching pseudo-reverberations to the signals that correspond to reverberations of the three-dimensional multi-channel acoustic signals for each listening position.

Description

  The present invention relates to a technique for presenting sound by a speaker in a room acoustic space, and more particularly to a spatial sound reproduction system using multi-channel sound.

  In a conventional sound reproducing apparatus based on a multi-channel sound system, a plurality of sound signals are individually reproduced by the same number or a larger number of speakers and in time alignment, so that a listener can be viewed from a plurality of directions. This makes it possible to present the desired sound impression to the listener.

  When performing sound reproduction with a plurality of speakers in a room, generally, the same signal (reference signal for adjustment) is input at the center position (reference listening position) of the assumed listening area, and the sound pressure from each speaker is The gain of the amplifier that drives the speaker is adjusted to be equal.

  In addition, at the reference listening position, adjustment is performed by inserting a frequency characteristic correction process in front of the amplifier so that the frequency characteristics of sounds coming from the speakers are as uniform as possible. Furthermore, in order to match the time for the sound to reach the reference listening position from each speaker, with respect to the speaker having the slowest arrival time, a delay process for the acoustic signal is inserted in front of the amplifier with respect to the speaker having the fastest arrival time, The time difference is adjusted by the delay processing.

  However, in an actual room acoustic space, in addition to the direct sound that arrives at the reference listening position earliest from the speaker, there is a reflected sound (indirect sound) that arrives after being reflected and delayed by the indoor wall surface. This reflected sound often degrades the desired acoustic impression to be presented to the listener. Therefore, in general, in order to reduce this reflected sound, an architectural acoustic design using a building material that reduces the reflectance of sound by the indoor wall surface is performed to solve this problem.

  On the other hand, as a spatial sound reproduction system using multi-channel sound provided in theaters such as movie theaters, a stereo sound reproduction technology that provides an excellent sound image localization effect at any location by providing speakers on individual chairs Is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2001-25086

  Dome theaters represented by planetariums, etc. have a perfect circle shape so that all positions on the wall (screen) on which the image is projected with respect to the reference listening position are equidistant in order to present ideal images. It is common to be taken. FIG. 9 shows the result of actually acquiring the acoustic signal in such a dome-shaped room acoustic environment. In FIG. 9, a direct sound is detected about 50 ms after the start of reproduction of the acoustic signal, and about 50 ms after the direct sound, another acoustic signal (hereinafter, referred to as a dome-shaped room acoustic environment) is separated from the reverberant sound of the direct sound. It can be seen that this is called “singular sound”. Such singular sounds are not preferable reproduction sounds for listeners. In this manner, as shown in FIG. 9, depending on the relative relationship between the position of the speaker arranged at a certain distance from the listening position in the dome theater space and the listening position in the listening area, the first direct sound that arrives from the speaker is delayed. Thus, the amplitude of the reflected sound, that is, the sound pressure level may increase, and it becomes extremely difficult to listen to the original sound signal with high quality in such a sound reproduction situation.

  That is, a space for presenting spatial acoustic quality equivalent to that of conventional multi-channel sound under inferior room acoustic conditions such as a dome theater (that is, an environmental condition in which singular sound is generated with a delay of 20 ms or more from the direct sound). A sound reproduction system is desired.

  In addition, a sound reproducing device for disposing a speaker in the vicinity of a passenger seat or increasing the intelligibility of sound by using a plurality of speakers as disclosed in Patent Document 1 has been developed so far. A system for reproducing an acoustic space with high quality has not been developed.

  In particular, it is unavoidable to make the wall surface an elliptical shape or a perfect circular shape for the purpose of video presentation in a dome theater. Another feature of the dome theater is that the entire wall surface is a screen. The screen is required to be as smooth as possible in order to improve the quality of the projected image, which increases the reflectivity for sound. Therefore, it is difficult to use architectural acoustic means to solve the problem.

  Therefore, in order to minimize the influence of the dome-shaped wall surface, it is considered that the most effective measure is to arrange the speaker as close as possible to the listener. However, the reproduced sound from the speaker placed near the listener and the acoustic impression from the speaker arranged at a considerable distance from the listener are different, and in addition, to achieve the original purpose of three-dimensional sound reproduction by multiple speakers Since the speaker arranged near the listening position is not easy, further contrivance is necessary.

  Therefore, even when multi-channel sound reproduction by arranging a plurality of speakers in a dome-shaped hall is performed by a conventional adjustment method, the sound impression often differs from the desired spatial impression.

  The present invention has been made in view of the above-described problems, and is under poor room acoustic conditions such as a dome theater (that is, a room acoustic condition in which a specific sound is generated with a delay of 20 ms or more from the direct sound). Another object of the present invention is to provide a spatial sound reproduction system using multi-channel sound with excellent sound image localization.

  In the spatial sound reproduction system of the present invention, a three-dimensional sound reproduction sound presented from a plurality of speakers arranged at remote positions from the listening position in a conventional manner and a binaural sound signal approximated to the three-dimensional sound are listened to. The reproduced sound reproduced by a plurality of speakers arranged in the vicinity is spatially mixed. Moreover, since the amplitude of the singular sound that occurs 20 ms or more later than the direct sound and the timing of the generated time differ depending on the seat position, the spatial mixing can be changed individually and arbitrarily depending on the seat.

  The spatial acoustic reproduction system of the present invention is a spatial acoustic reproduction system that reproduces three-dimensional multi-channel sound in an indoor acoustic environment, and spatially reproduces the three-dimensional multi-channel acoustic signal in the indoor acoustic environment. In order to reproduce a plurality of spatially distributed speakers and binaural reproduction acoustic signals converted by binaural processing based on the three-dimensional multi-channel acoustic signals, the listening is performed for each of a plurality of listening positions in the room acoustic environment. A binaural-arranged speaker composed of a plurality of speakers arranged in a predetermined position as a position in the vicinity of both ears of a person, a reproduced sound reproduced by the plurality of spatially-arranged speakers, and reproduced by the speakers arranged near the binaural The binaural sound signal for the three-dimensional multi-channel sound signal so that the phase of the sound to be reproduced matches. A spatial acoustic reproduction device that adjusts the time difference and generates the binaural reproduction acoustic signal to which a pseudo-reverberation sound corresponding to the reverberation sound of the three-dimensional multi-channel acoustic signal is added for each listening position. To do.

  In the spatial acoustic reproduction system of the present invention, the room acoustic environment is a spatial environment in which a specific sound is generated in which the reproduced sound reproduced by the plurality of spatially arranged speakers is delayed by 20 ms or more from the direct sound. And

  In the spatial sound reproduction system of the present invention, in order to reproduce an acoustic signal obtained by multiplexing and synthesizing the three-dimensional multi-channel acoustic signal, each listening position is arranged at a predetermined position as a front position of the listener. The speaker further includes a speaker arranged in front of the listening position.

  According to the present invention, even in a poor indoor acoustic environment such as a dome theater where it has been difficult to reproduce high-quality spatial sound with the prior art, for example, an acoustic content created by a three-dimensional multi-channel sound production system is desired. It will be possible to play with the spatial sound quality.

It is a schematic block diagram of the spatial sound reproduction system of one Embodiment by this invention. It is a figure which shows the example of arrangement | positioning of the multi-channel space arrangement | positioning speaker and the binaural vicinity arrangement | positioning speaker in the spatial sound reproduction system of 1st Embodiment by this invention. (A), (B) is a figure which shows the example of arrangement | positioning of the binaural vicinity arrangement | positioning speaker in the spatial sound reproduction system of 1st Embodiment by this invention. It is a block diagram of the sound reproduction apparatus in the spatial sound reproduction system of 1st Embodiment by this invention. It is a figure which shows an example measured about the acoustic signal in the spatial acoustic reproduction system of 1st Embodiment by this invention. (A), (B) is a figure which shows the example of arrangement | positioning of the binaural vicinity arrangement | positioning speaker in the spatial sound reproduction | regeneration system of 2nd Embodiment by this invention. It is a block diagram of the sound reproduction apparatus in the spatial sound reproduction system of 2nd Embodiment by this invention. It is a figure which shows an example measured about the acoustic signal in the spatial acoustic reproduction system of 2nd Embodiment by this invention. It is a figure which shows an example which measured the acoustic signal in the dome-shaped room acoustic environment based on the conventional multichannel acoustic system.

  First, with reference to FIGS. 1-4, the spatial sound reproduction system 10 of 1st Embodiment by this invention is demonstrated. FIG. 1 is a schematic configuration diagram of a spatial sound reproduction system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an arrangement example of the multi-channel spatially arranged speakers and the binaurally arranged speakers in the spatial sound reproduction system according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating an arrangement example of speakers arranged near both ears in the spatial sound reproduction system according to the first embodiment of the present invention. FIG. 4 is a block diagram of the sound reproducing device in the spatial sound reproducing system according to the first embodiment of the present invention.

[First Embodiment]
Referring to FIG. 1, it is assumed that the room acoustic environment of the dome-shaped hall H (that is, a spatial environment in which singular sound is generated with a delay of 20 ms or more from the direct sound). The dome-shaped hole H in FIG. 1 is merely an example, but in general, a singular sound as shown in FIG.

  In the spatial acoustic reproduction system 10 of the present embodiment, N-channel spatially arranged speakers 30-1, 30-2, 30-3,..., 30-N reproduce acoustic content for a three-dimensional multichannel acoustic signal. In order to do so, it is spatially distributed in the room acoustic environment, for example, provided on or near the wall surface of the dome-shaped hole H. The arrangement position of the spatially arranged speaker 30-N can be set to the front arrangement, the rear arrangement, or the peripheral arrangement with respect to the listener of each seat S. The arrangement position of the spatial arrangement speaker 30-N itself is the same as that of the present invention. Not the subject. For example, it can arrange | position so that the sound pressure from each space arrangement | positioning speaker 30-N may become equal in the center position (reference | standard listening position) of the assumed listening area.

  Each seat S is provided with two left and right second speakers that generate binaural reproduction sound whose volume is adjusted for each listening position in the vicinity of both ears of the listener (hereinafter referred to as “arrangement near both ears”). Called "speakers"). For example, assuming that the distance between both ears is 0.15 m, it is preferable to install the binaural proximity speaker 40 in the seat S within 0.15 m of the ear position assumed in advance.

  As shown in FIGS. 1 and 2, in this embodiment, the sound reproducing device 20 includes N-channel spatially arranged speakers 30-1, 30-2, 30-3,. This is a device for controlling the phase and sound pressure level of the reproduced sound from the binaural-arranged speaker 40 comprising two left and right second speakers provided in S. The sound reproducing device 20 can be configured by a computer and can be realized by control of a central processing unit (CPU) or the like. That is, the CPU can appropriately read a program in which processing contents for realizing the function of each component are described from a predetermined storage unit, and realize the function of each component on the computer.

  FIG. 3A is a cross-sectional view of the seat S as viewed from the side, and the binaural-arranged speaker 40 is disposed at a predetermined seat height h. FIG. 3B is a rear view as seen from the back of the seat S, and the distance between the two left and right second speakers w may be set to be about 0.15 m to 0.30 m.

  As shown in FIG. 4, the sound reproducing device 20 according to the present embodiment includes an N-channel sound signal reproducing storage unit 201, an acoustic signal reproduction control unit 202, a listening position table storing unit 203, and a listening position time difference for each channel. A control unit 204, a pseudo reverberation generation / addition unit 205, a binaural processing unit 206, and volume adjustment units 207 and 208 are provided.

  The storage unit 201 for N-channel acoustic signal reproduction stores acoustic content for a three-dimensional multi-channel acoustic signal that is reproduced in the room acoustic environment of the dome-shaped hall H. Such sound content is created by a producer using, for example, a three-dimensional multi-channel sound production system, and is not specific to the room acoustic environment of the dome-shaped hall H but can be arbitrary.

  The acoustic signal reproduction control unit 202 generates an acoustic signal to be reproduced for the N-channel spatially arranged speaker 30-N for the acoustic content stored or recorded in the N-channel acoustic signal reproduction storage unit 201.

  The listening position seat table storage unit 203 stores information on the position coordinates of each seat S. This position table may be of any type as long as the distance and direction from each of the N-channel spatially arranged speakers 30-N to each seat S can be specified.

  The channel-by-channel listening position time difference control unit 204 has the position coordinates of each seat S (that is, each listening position) stored in the listening position table storage unit 203 with respect to the acoustic signals of each channel reproduced by the acoustic signal reproduction control unit 202. Based on the information of the position coordinates, the time difference of the arrival time of the reproduced sound at each listening position is controlled for each channel. In this time difference control, a delay amount is measured in advance for the audio content stored or recorded in the N-channel audio signal reproduction storage unit 201, and the delay is adjusted according to the reproduction time by the audio signal reproduction control unit 202.

  The pseudo-reverberant sound generation / addition unit 205 generates a pseudo-reverberant sound that directly uses the N-channel acoustic signals for which the time difference in the arrival time of the reproduced sound at each listening position is controlled for each channel. Append. Although any reverberation sound generation algorithm can be adopted, for example, as shown in FIG. 9, a reverberation sound whose sound pressure level decreases exponentially is added to the acoustic signal of each channel.

  The binaural processing unit 206 inputs an acoustic signal of each channel to which a reverberant sound is added, and converts it into a binaural reproduction acoustic signal using a known head related transfer function. The binaural processing unit 206 multiplex-synthesizes the acoustic signals of the respective channels to which the reverberation sound is added as acoustic signals for the binaural-arranged speaker 40 including the left and right second speakers.

  The volume adjusting unit 207 adjusts the volume (sound pressure level) of the acoustic signal of each channel from the acoustic signal reproduction control unit 202, and generates an N-channel acoustic signal for the N-channel spatially arranged speaker 30-N.

  The volume adjusting unit 208 adjusts the volume (sound pressure level) of the acoustic signal for the binaural-arranged speaker 40 from the binaural processing unit 206 and generates the acoustic signal for the binaural-arranged speaker 40.

  A more specific example of the spatial sound reproduction system 10 of the present embodiment will be described.

(Speaker placed near both ears)
In the spatial sound reproduction system 10 of the present embodiment, in addition to the spatially arranged speakers 30-N arranged at a relatively far distance from the conventional listener, a second speaker is provided near both ears of each listener. A certain near-ear speaker 40 is arranged. The binaural speaker 40 is composed of two speakers arranged near the left and right ears of the listener's head, and the head of a three-dimensional sound signal reproduced by speakers arranged in various directions such as the spatially arranged speaker 30-N. This is converted into a binaural playback sound signal using a partial transfer function and played back. The three-dimensional sound signal input to the binaural signal conversion by such a head-related transfer function is a plurality of sound signals having sound information in the three-dimensional direction created by the three-dimensional sound production system used by the sound content producer. be able to.

(Sound reproduction device)
In the spatial sound reproduction system 10 shown in FIG. 1, only one spatially-arranged speaker 30-N (in FIG. 2, only one spatially-arranged speaker 30-N is shown, but the direction of arrival of the sound required at a certain distance from the listening position is shown. A plurality of N speakers required to reproduce the sound are arranged in the space, and a spatial impression approximate to the three-dimensional sound reproduced by the N-channel spatially arranged speakers 30-N intended by the producer of the audio content. As obtained, a binaural speaker 40 is installed for each seat S.

  What is important here is that the reproduced sound reproduced by the near-ear speakers 40 installed in each seat S is more than the reproduced sound arriving from the N-channel spatially arranged speakers 30-N to the position of each seat S. Is presented to the listener earlier in time. For this reason, if this time relationship is not matched, the spatial impression of the sound will be different. Therefore, the distance from each space-arranged speaker 30-N to the listening position is actually measured at the listening position for each seat S, and stored in the listening position coordinate storage unit 203 as listening position coordinate information in advance.

  The sound reproduction device 20 delays the N-channel acoustic signal by the arrival time of the sound calculated from the distance from each spatially arranged speaker 30-N to the listening position and the sound arrival time by the channel-specific listening position time difference control unit 204, Every time, the time (that is, the phase) of the reproduced sound of the spatially arranged speaker 30-N and the binaural speaker 40 is matched.

  Furthermore, since the reproduced sound reproduced from the spatially arranged speaker 30-N becomes a reproduced sound with a certain reverberation to which a rear reverberant sound (see FIG. 9) due to the room shape of the dome-shaped hall H is added. The sound reproducing device 20 measures the rear reverberation characteristics at the positions of the seats S in order to reproduce the reverberation in the binaural vicinity speaker 40 by the pseudo reverberation generation / addition unit 205 in the same manner. A pseudo reverberation sound equivalent to the rear reverberation characteristic is generated and added to the three-dimensional acoustic signal of each channel. A pseudo reverberation pattern equivalent to the actually measured rear reverberation characteristic may be stored in a storage unit (not shown) and sequentially read out.

  The sound reproduction apparatus 20 performs binaural processing based on the head-related transfer function by the binaural processing unit 206 with respect to the three-dimensional sound signal of each channel to which the pseudo reverberation sound is added in this manner, and the volume adjustment unit 208 After the volume adjustment, an acoustic signal to be reproduced by the near-ear speaker 40 is generated.

  The spatial impression reproduced by the binaural speaker 40 will be described in more detail. The signal generated by the binaural processing unit 206 is received in each listening area of the actual dome-shaped hall H (the area where the seat S is provided). Depending on the relative positional relationship between the position and each space-arranged speaker 30-N, the acoustic space impression (particularly the sense of sound direction) may differ depending on the listening position. In this case, the spatial impression actually reproduced by the binaural speaker 40 must change according to the change depending on the listening position. Therefore, it is preferable to obtain the coordinates (xi, yi, zi) of each listening position by actual measurement assuming a polar coordinate space of each listening position centering on the assumed center position (reference listening position) of the listening area. By storing this coordinate data as listening position coordinate information in the listening position coordinate storage unit 203, the channel-specific listening position time difference control unit 204 causes the spatially arranged speakers 30-N of each channel and the near-ear speakers 40 to be used. It is possible to match the spatial impression (sound arrival direction) of the reproduced sound reproduced in the above.

  The volume adjusters 207 and 208 adjust the output level of each speaker so that a desired three-dimensional sound space impression can be obtained in the process of reproduction by the spatially arranged speakers 30-N and the binaural speakers 40, respectively. .

  FIG. 5 shows an example of measuring the acoustic signal in the spatial sound reproduction system of the embodiment. As is clear from the comparison with FIG. 9, it can be seen that the singularity decreases.

  As described above, according to the present embodiment, even in a poor room acoustic environment such as a dome theater where high-quality spatial sound reproduction was difficult with the prior art, for example, in a three-dimensional multi-channel sound production system The created acoustic content can be reproduced with desired spatial acoustic quality.

  Next, a spatial sound reproduction system 10 according to a second embodiment of the present invention will be described with reference to FIG. 1, FIG. 6, and FIG. Similar components are denoted by the same reference numerals. FIG. 6 is a diagram illustrating an arrangement example of speakers arranged near both ears in the spatial sound reproduction system according to the second embodiment of the present invention. FIG. 7 is a block diagram of the sound reproducing device in the spatial sound reproducing system according to the second embodiment of the present invention.

[Second Embodiment]
Also in the present embodiment, the room acoustic environment of the dome-shaped hall H as shown in FIG. 1 (that is, a spatial environment in which a specific sound that occurs 20 ms or more behind the direct sound occurs) is assumed.

  In the spatial sound reproduction system 10 of the second embodiment, as in the first embodiment, N-channel spatially arranged speakers 30-1, 30-2, 30-3,. It is provided on or near the wall of H. The arrangement position of the spatial arrangement speaker 30-N can be set to the front arrangement, the rear arrangement, or the peripheral arrangement with respect to the listener of each seat S. For example, it can be arranged so that the sound pressure from each speaker is equal at the center position (reference listening position) of the assumed listening area.

  Further, in the spatial sound reproduction system 10 of the second embodiment, as in the first embodiment, binaural reproduction sound whose volume is adjusted for each listening position is provided in each seat S in the vicinity of both ears of the listener. Both near-ear speakers that are two left and right second speakers are provided.

  However, in the spatial sound reproduction system 10 of the second embodiment, as shown in FIG. 6, the first embodiment is that a third speaker (hereinafter referred to as “listening position front speaker”) is provided in front of the listening position. Is different.

  Therefore, the sound reproducing device 20 according to the present embodiment includes an N-channel spatially arranged speaker 30-N, a binaural-arranged speaker 40 including two left and right second speakers provided in each seat S, and a listening position front speaker. 50 is configured as a device for controlling the phase and sound pressure level of the reproduced sound from 50. The sound reproducing device 20 of this embodiment can also be configured by a computer, and can be realized by control of a central processing unit (CPU) or the like. That is, the CPU can appropriately read a program in which processing contents for realizing the function of each component are described from a predetermined storage unit, and realize the function of each component on the computer.

FIG. 6A is a cross-sectional view of the seat S as viewed from the side, the binaural vicinity speaker 40 is disposed at a predetermined seat height h, and the listening position front speaker 50 is predetermined. It is arranged at the position of the seat height h ₂ (h ₂ ≦ h). FIG. 6B is a rear view as seen from the rear of the seat S, and the distance w between the two left and right second speakers may be set to be about 0.15 m to 0.30 m. The front speaker 50 is preferably arranged at the center (w ₁ = w ₂ = w / 2) of each speaker in the binaural proximity speaker 40 from the viewpoint of volume balance. The binaural proximity speaker 40 may be composed of a plurality of speakers, but in the following description, it will be described as a single speaker.

  As shown in FIG. 7, the sound reproducing device 20 according to the present embodiment includes an N-channel sound signal reproducing storage unit 201, an acoustic signal reproduction control unit 202, a listening position table storing unit 203, and a listening position time difference for each channel. Since the control unit 204, the pseudo reverberation generation / addition unit 205, the binaural processing unit 206, and the volume adjustment units 207 and 208 are the same as those in the first embodiment, description thereof will be omitted.

  The sound reproduction device 20 according to the present embodiment further includes a pseudo reverberation sound generation / addition unit 210, a channel multiplexing processing unit 211, and a volume adjustment unit 212.

  The pseudo-reverberant sound generation / addition unit 210 generates a pseudo-reverberant sound that uses this as a direct sound for each N-channel acoustic signal in which the time difference of the playback sound arrival time at each listening position is controlled for each channel. Append. Although any reverberation sound generation algorithm can be adopted, for example, as shown in FIG. 9, a reverberation sound whose sound pressure level decreases exponentially is added to the acoustic signal of each channel.

  The channel multiplexing processing unit 211 receives the acoustic signals of the respective channels to which the reverberation sound has been added by the pseudo reverberation sound generation / addition unit 210 and multiplex-synthesizes them as the acoustic signals for the listening position front speaker 50.

  The volume adjusting unit 212 adjusts the volume (sound pressure level) of the acoustic signal for the listening position front speaker 50 from the channel multiplex processing unit 211, and generates the acoustic signal for the listening position front speaker 50.

  A more specific example of the spatial sound reproduction system of this embodiment will be described.

(Listening position front speaker)
In the spatial sound reproduction system 10 of the present embodiment, in addition to the spatially arranged speakers 30-N arranged at a relatively far distance from the conventional listener, a second speaker is provided near both ears of each listener. A binaural near speaker 40 and a listening position front speaker 50 are arranged. The binaural speaker 40 is composed of two speakers arranged near the left and right ears of the listener's head, and the head of a three-dimensional sound signal reproduced by speakers arranged in various directions such as the spatially arranged speaker 30-N. This is converted into a binaural playback sound signal using a partial transfer function and played back. The three-dimensional sound signal input to the binaural signal conversion by such a head-related transfer function is a plurality of sound signals having sound information in the three-dimensional direction created by the three-dimensional sound production system used by the sound content producer. be able to. In addition, the listening position front speaker 50 reproduces an acoustic signal obtained by multiplexing and synthesizing three-dimensional acoustic signals to be reproduced by speakers arranged in various directions such as the spatially arranged speaker 30-N.

  In the near binaural speaker 40, a three-dimensional sound signal reproduced by speakers arranged in various directions such as the spatially arranged speaker 30-N is converted into a binaural reproduction acoustic signal using a head-related transfer function and reproduced. However, only by binaural reproduction using the head-related transfer function, the sound image in front of the listener is localized in the head, and the problem that it is difficult to hear the sound that should be heard from the front is known. In order to solve this problem, the listening position front speaker 50 reproduces the sound to be heard from the front of the listener, thereby improving the three-dimensional sound impression as compared with the reproduction by the binaural speaker 40 alone. be able to.

(Sound reproduction device)
Also in the present embodiment, the reproduced sound arriving from the N-channel spatially arranged speaker 30-N to the position of each seat S is reproduced by the binaural speakers 40 and the listening position front speakers 50 installed in each seat S. The reproduced sound is presented to the listener earlier in time. For this reason, if this time relationship is not matched, the spatial impression of the sound will be different. Therefore, the distance from each space-arranged speaker 30-N to the listening position is actually measured at the listening position for each seat S, and stored in the listening position coordinate storage unit 203 as listening position coordinate information in advance.

  The sound reproduction device 20 delays the N-channel acoustic signal by the arrival time of the sound calculated from the distance from each spatially arranged speaker 30-N to the listening position and the sound arrival time by the channel-specific listening position time difference control unit 204, Every time, the time (that is, the phase) of the reproduced sound of the spatially arranged speaker 30-N, the near-ear speaker 40, and the listening position front speaker 50 is matched.

  Furthermore, the reproduced sound reproduced from the spatially arranged speaker 30-N becomes a reproduced sound having a certain reverberation to which a rear reverberant sound (see FIG. 9) due to the room shape of the dome-shaped hall H is added. The sound reproduction apparatus 20 uses the pseudo reverberation generation / addition units 205 and 210 to reproduce the reverberation in the same manner in the binaural speakers 40 and the listening position front speakers 50, so that the rear reverberation characteristics at the positions of the seats S are obtained. Is measured, and a pseudo reverberation sound equivalent to the actually measured rear reverberation characteristic is generated and added to the three-dimensional sound signal of each channel. A pseudo reverberation pattern equivalent to the actually measured rear reverberation characteristic may be stored in a storage unit (not shown) and sequentially read out.

  For the three-dimensional sound signal of each channel to which the pseudo reverberation sound is added in this way, the sound reproducing device 20 generates sound signals suitable for each speaker by the binaural processing unit 206 and the channel multiplexing processing unit 211. After adjusting the volume by the volume adjusters 208 and 212, the sound signals to be reproduced by the binaural vicinity speaker 40 and the listening position front speaker 50 are generated.

  In more detail regarding the spatial impression reproduced by both the near-ear speaker 40 and the listening position front speaker 50, each listening position and each listening position in the listening area (the area where the seat S is provided) of the actual dome-shaped hall H will be described. According to the relative positional relationship with the spatially arranged speaker 30-N, the channel-specific listening position time difference control unit 204 controls the spatially arranged speaker 30- of each channel so that the acoustic space impression (especially the direction of sound) is the same depending on the listening position. It is possible to match the spatial impression (the sound arrival direction) of the reproduced sound reproduced by N, the binaural speaker 40 and the listening position front speaker 50.

  The sound volume adjusting units 207, 208, and 212 can obtain a desired three-dimensional acoustic space impression in the process of reproduction by the spatially arranged speaker 30-N, the binaural speaker 40, and the listening position front speaker 50, respectively. Adjust the output level of each speaker.

  FIG. 8 shows an example of measuring the acoustic signal in the spatial acoustic reproduction system of the embodiment. As is clear from the comparison with FIG. 9, it can be seen that the singularity is decreased, and the singularity is decreased similarly to FIG. 5.

  As described above, according to the present embodiment, even in a poor room acoustic environment such as a dome theater where high-quality spatial sound reproduction was difficult with the prior art, for example, in a three-dimensional multi-channel sound production system The created acoustic content can be reproduced with desired spatial acoustic quality.

  According to the present invention, even in a poor indoor acoustic environment such as a dome theater where it has been difficult to reproduce high-quality spatial sound with the prior art, for example, an acoustic content created by a three-dimensional multi-channel sound production system is desired. Therefore, it is useful for any application for reproducing a three-dimensional multi-channel acoustic signal.

DESCRIPTION OF SYMBOLS 10 Spatial sound reproduction system 20 Sound reproduction apparatus 30-1, 30-2, 30-3, ..., 30-N N channel spatial arrangement speaker 40 Binaural speaker 50 Listening position front speaker 201 N channel sound signal reproduction Storage unit 202 Acoustic signal reproduction control unit 203 Listening position table storage unit 204 Listening position time difference control unit by channel 205, 210 Pseudo reverberation sound generation addition unit 206 Binaural processing unit 207, 208, 212 Volume adjustment unit 211 Channel multiplexing processing unit

Claims (3)

A spatial sound reproduction system for reproducing three-dimensional multi-channel sound in a room acoustic environment,
A plurality of spatially arranged speakers spatially dispersed in the room acoustic environment for reproducing a three-dimensional multi-channel acoustic signal;
In order to reproduce a binaural reproduction acoustic signal converted by binaural processing based on the three-dimensional multi-channel acoustic signal, a position near the listener's ears is determined for each of a plurality of listening positions in the room acoustic environment. A binaural proximity speaker composed of a plurality of speakers arranged at a position;
The time difference of the binaural playback sound signal with respect to the three-dimensional multi-channel sound signal is adjusted so that the reproduced sound reproduced by the plurality of spatially arranged speakers and the reproduced sound reproduced by the binaural speakers are matched in phase. And a spatial acoustic reproduction device that generates the binaural reproduction acoustic signal to which a pseudo-reverberation sound corresponding to the reverberation sound of the three-dimensional multi-channel acoustic signal is added for each listening position;
A spatial sound reproduction system comprising:   The spatial acoustic environment according to claim 1, wherein the room acoustic environment is a spatial environment in which a reproduced sound reproduced by the plurality of spatially arranged speakers generates a singular sound that is delayed by 20 ms or more from the direct sound. Playback system.   In order to reproduce an acoustic signal obtained by multiplexing and synthesizing the three-dimensional multi-channel acoustic signal, the speaker further includes a listening position front arrangement speaker arranged at a predetermined position as a listener's front position for each listening position. The spatial sound reproduction system according to claim 1 or 2.